Engineers take a new line on road safety

Minnesota has one of the lowest traffic fatality rates in the nation, but 70 percent of those deaths happen on rural highways.

In Otter Tail County, crews installed new wider white stripes along the edge of a busy stretch of road, along with a reflective yellow center line.

The changes are part of the effort to spend money on proactive highway safety improvements, even on roads that haven't turned deadly. It's a change in focus driven by closer analysis of crash data.

"The bulk of our crashes are still random," said Otter Tail County engineer Rick West. "If I look at my whole system there are very few miles that are two or four mile segments that we have a lot of crashes, and so that drives you to the systematic approach."

That approach is better because a map of Otter Tail county accidents shows a rash of red dots spread across the county. Many are cases where people ran off the road and rolled over.

MnDOT Senior Engineer Mark Vizecky says research shows simple safety improvements can make a big difference. A wider stripe on the edge of road makes for better night vision. Trimming the edge of the pavement from a vertical dropoff to an angle reduces the number of rollovers that happen when drivers drift onto the shoulder and overcorrect to get back on the road. Reflective signs on curves warn drivers to slow down.

Vizecky says those are all effective, relatively cheap ways to make roads safer.

"And that's really what the program's trying to focus on, to catch that low hanging fruit," he said. "You can do thousands of miles of your system for relatively low cost, to try to cover more of the system since those accidents or crashes really are random."

Many Minnesota counties are putting more emphasis on improving highway safety. The state will require each county to develop a comprehensive highway safety plan over the next couple of years.

The 12 west central Minnesota counties in MnDOT district 4 will spend $1.6 million this year to paint wider stripes on 1,700 miles of highway, put reflectors on 320 curves and add 50 miles of rumble strips -- the pavement ridges that tell you you're about to run off the road.

The highway safety program is spending $13 million on
similar projects statewide.

West says it would be great to rebuild narrow rural roads and make them wider. But at $600,000 a mile, that's not likely to happen.

In the meantime, West is convinced simple changes can save lives. But he's also realistic about the limitations of engineering. It still comes down to the decisions drivers make. And looking at the accident map, West finds a lot of drivers are making bad decisions.

He says alcohol is a factor in at least 50 percent of fatal accidents in his county.

"No amount of engineering is going to help a lot of those," he said. "If you're driving twice the advised speed approaching a curve, you aren't going to make it."

But West says engineers can make the highway as forgiving as possible.

"If we can save two lives of three lives or one life, we're doing the right thing," he said. "That's going to be the test of whether what we're doing is effective. We think it is. We think the studies and research that has been done proves that. But the ultimate proof is a reduction in fatalities and serious injury crashes."

Gallery

A new six-inch reflective stripe on the edge of the road will be much brighter at night than the old four inch painted stripe.MPR Photo / Dan GundersonView full galleryAn interactive highway mapping software allows engineers to quickly analyze crash data for the last ten years and look for trends.MPR Photo / Dan Gunderson